1. Field of the Invention
The present invention relates generally to a coordinate measuring apparatus for measuring an input position of a coordinate indicating apparatus, such as a finger or a stylus pen, and a method of manufacturing the same.
2. Description of the Related Art
In recent years, smart phones or tablet Personal Computers (PCs) have increased in popularity. A smart phone or a tablet PC mainly includes a touch screen, through which a user may enter an input at a specific coordinate by using a finger or a stylus pen.
The touch screen may operate using electrical methods, infrared methods, ultrasonic methods, etc. Examples of the electrical methods may include a Resistance (R) type touch screen and a Capacitive (C) type touch screen.
To date, R type touch screens, which recognize both a finger of a user and a stylus pen, are more commonly used, but the R type touch screens often have a problem caused by reflection due to a layer of air between transparent conducting film layers, for example, Indium Tin Oxide (ITO) layers. That is, transmittance of light transmitted from a display is lowered by a layer of air between ITO layers, and light reflection on a screen increases.
Accordingly, the use of C type touch screens has recently increased. The C type touch screens detect a difference between electrostatic capacities of a transparent electrode generated by a contact of an object. However, because it is difficult for the C type touch screens to physically distinguish a hand from a pen, the C type touch screens often generate operation errors due to an unintended contact of a hand during use thereof.
To address some of the drawbacks of the R and C type touch screens, Electro Magnetic Resonance (EMR) has been used, by including a separate coordinate measuring apparatus in addition to a C type touch screen.
For example, some recent smart phones or tablet PCs include both a C type panel and an EMR type panel. These smart phones or tablet PCs can detect inputs of both a portion of a body of a user and a stylus pen, in which case a C type panel can detect, for example, an input by a portion of a body of a user, e.g., a finger, and an EMR type panel can detect an input by another device, such as a stylus pen. However, when a user inputs an instruction to a smart phone or tablet PC while holding a stylus pen, a portion of a hand of the user often contacts the touch screen. Accordingly, the C type panel may still recognize the portion of the hand of the user as an instruction for touching a specific object, and thus an error will still occur.